The present invention relates to a head for the linear dimension checking of a mechanical piece, including a support structure with a casing that defines a recess and a longitudinal geometric axis, and an arm-set, movable with respect to the support structure.
The invention also relates to an apparatus for the linear dimension checking of mechanical pieces, including at least a head for the linear dimension checking of mechanical pieces and a support and reference system, with a substantially stationary structure, for supporting and locating the head in a definite checking position.
Moreover, the invention relates to a method for the linear dimension checking of a mechanical piece, by means of an apparatus with at least a gauging head, including a zero setting phase carried out on a master piece, for displacing the head to a definite checking position, and a checking phase.
Furthermore, the invention relates to an inductive type transducer for use in heads for the linear dimension checking with a support structure and an arm, movable with respect to the support structure, for generating electric signals depending on the position of the arm with respect to the support structure, the transducer including windings and a core, made from ferromagnetic material, housed within the windings and movable with respect to them, the transducer further including a hollow support with a first housing and a spool, arranged in the first housing, with annular seats for the windings.
The invention also relates to an apparatus for the linear dimension checking of a mechanical piece, with a gauging head for cooperating with the piece, a transducer at least partially included in the gauging head for generating electric signals indicative of the dimensions of the piece, a processing unit and electric coupling means between the head and the processing unit.
There are known many types of gauging, or measuring, heads for the inspection of mechanical pieces in benches, transfer lines or in the course of the machining in machine tools in applications of the so-called xe2x80x9cin-processxe2x80x9d type.
Even though the known heads ensure good performance insofar as the repeatability and the reliability are concerned, they are generally dedicated to specific types of applications and do not allow a broad flexibility of use.
In other circumstances, even though the heads would be suitable for a number of applications, they require lengthy, expensive and toilsome retooling operations.
The transducer devices of the known heads, for example of the linear voltage differential transformer, or half-bridge type, with reciprocally movable windings and core have a linear performance in an extremely limited area of displacement between the core and the windings, hence permitting limited measuring ranges. Moreover, these transducer devices have a structure that is delicate and particularly sensitive to temperature variations that cause undesired drifts, known as xe2x80x9cthermal driftsxe2x80x9d, in the course of the operation of the heads.
The known heads also include cables with electric wires that enable the sending of signals from the associated transducers to the processing units, and connectors at the free end of the cables. The connectors of the known heads have elements intended to be coupled to each other, for example, by means of a threaded coupling, that requires particular care on behalf of the operator for achieving the appropriate locking and sealing.
There are also known apparatuses comprising frames for supporting these heads, for example, supports for supporting and referring a pair of heads in applications for the diameter checking. The heads can be coupled to the support in an adjustable way, both reciprocally and with respect to the support. Apparatuses of this type are utilized, for example, for the diameter checking of pieces in the course of the machining in machine tools, more specifically, in grinding machines. The component parts of the apparatus, more specifically the gauging heads, can be subject to accidental and undesirable collisions, frequently occurring especially in the workshop environment where there are applications of the xe2x80x9cin-processxe2x80x9d type. These collisions can alter the checking position of the heads, besides cause damage to the actual heads.
An object of the present invention is to provide gauging or measuring heads for the linear dimension checking of mechanical pieces that guarantee high standards of repeatability and accuracy, are particularly reliable, versatile and inexpensive, hence overcome the disadvantages of the known heads.
It is another object of the invention to provide component parts for gauging heads, in particular transducers and connectors, that contribute to improve the performance of the heads and reduce their manufacturing costs, and make their use extremely simple and flexible.
Yet another object of the invention is to provide checking apparatuses that utilize gauging or measuring heads that, while guaranteeing high standards of repeatability and accuracy, are particularly safe and flexible in use, and need only easy and quick set-up operations.
It is also object of the present invention to provide a method for the linear dimension checking implemented by means of an apparatus with at least a gauging or measuring head that is particularly simple and flexible in use.
A still further object of the invention is to provide a checking apparatus with at least a gauging or measuring head and means for the connection to a processing unit that are particularly reliable, compact and can be easily and quickly replaced.
These and other objects are achieved by heads, component parts, apparatuses and a checking method as defined in the claims provided at the end of the description.
The heads, the apparatuses, the component parts and the method according to the invention provide particular advantages, as described in the following description.